Patients who had a major operation and the elderly having lower digestive capacity cannot digest food to an absorbable state, and therefore, cannot take sufficient nutrition. It reduces resistance to illness and a recuperative power. Liquid nutritional supplements are used for the maintenance or management of nutrition in such patients, and particularly used for tube feeding of nutrition when oral dietary intake is difficult. Liquid nutritional supplements administered using a tube are called enteral nutrients, which are administered to the stomach, duodenum or jejunum from a nasal tube, gastric fistula or intestinal fistula. According to the symptom, oral intake may be employed for patients capable of oral ingestion.
Liquid nutritional supplements, enteral nutrients among others, are essential for the nutritional maintenance of postoperational patients. Enteral nutrients contain digested nutrients and elemental nutrients and are supplied in the form of a liquid. The incidence of diarrhea, gastroesophageal reflux and misswallowing as side effects of the intake of enteral nutrients is high, which poses problems for the QOL of patients themselves and clinical workers. Needless to say, the onset of diarrhea and the like is also observed as side effects of oral administration of the nutrients.
It is considered that diarrhea, a side effect of liquid nutritional supplements, is caused by lower gastrointestinal physiological function due to fasting before and after operation or operative stress, as well as long-term non-intake of nutrition from the gastrointestinal tract due to postoperative central venous nutrition and the like, and lower gastrointestinal physiological function due to fasting before and after operation. It is also observed in patients with markedly degraded digestive and absorptive capacity due to aging, such as the elderly and the like, and babies and infants having immature digestive and absorptive capacity.
Another major problem of liquid nutritional supplements is gastroesophageal reflux. Patients in the dorsal position during intragastric administration of liquid nutritional supplements by tube feeding or from a gastric fistula may develop aspiration pneumonia because of invasion of gastric contents, which refluxed into the esophagus, to the trachea or lung. Since aspiration pneumonia may sometimes be fatal to a sick person, it is also an extreme threat to the medical workers responsible for protecting patients' lives. Thus, prophylaxis and prevention of gastroesophageal reflux causing misswallowing has been desired.
No effective measures to deal with these side effects caused by the administration of liquid nutritional supplements have been found heretofore, and change, reduction or discontinuation of liquid nutritional supplements, or administration of a therapeutic drug suitable for the symptom and the like have been employed.
As for diarrhea induced by lactose, a report has documented that administration of five kinds of nucleic acids of adenylic acid, guanylic acid, uridylic acid, cytidylic acid and inosinic acid, which are nucleic acids forming RNA, in admixture with a standard diet suppresses diarrhea (R. Norton et al, “Brazilian Journal of Medical and Biological Research”, 2001, vol. 34, P. 195-202). However, this report merely suggests a possibility that simultaneous administration of five kinds of nucleic acids may act on the recovery from gastrointestinal mucosa inflammation, for suppression of diarrhea symptoms caused by a particular component of lactose, and no suggestion of effect is provided when one kind thereof is lacking, i.e., when RNA is not formed. In addition, the report contains no description relating to nutritional compositions or liquid nutritional supplements.
As enteral nutrients containing glutamic acid, a liquid preparation containing 24-147 mM (0.36-2.1 w/v %) of free glutamic acid, which is efficiently absorbed and effective as an energy source (JP-A-7-330583), and a composition for the treatment of gastric and intestinal dysfunction, which contains 9.0-17 wt % (in total amino acid composition) of free amino acid including glutamic acid (JP-A-2003-530411), are known. However, used for the both is free glutamic acid, and a glutamic acid salt is not suggested at all. In addition, these publications show enteral nutrients containing glutamic acid as an energy source and nutrient source, and suppression of side effects such as diarrhea and the like, which are developed by enteric nutrient administration of glutamic acid, is not suggested.